The retro template runs at 60 FPS like any other C2 project. However, the template does turn on pixel rounding -- under project settings -- which can make movement look less smooth, giving the illusion of a lower framerate.
Honestly, there's no good way to actually limit the FPS, and I definitely wouldn't recommend slowing down the game on purpose by overloading the GPU/CPU -- this would have huge effects on power drain, amongst other things.
One way to fake an FPS limit would be to update your events every other frame -- for example, by incrementing a global variable by 1 every frame and only updating all other events if this value is even. This will effectively run your event logic at 30 FPS assuming the game is rendering at 60 FPS. However, using this method you'd have to roll all of your own movements, as behaviors would still update 60 times per second.